The present invention relates to an embedded capacitor device having a common coupling area and, more particularly, to an embedded capacitor device that can be embedded within a circuit board and provide a common coupling area for an integrated circuit.
Capacitors are electrical devices capable of storing or absorbing electrical charges. With the charge-storing capacity, capacitors have broad applications in the design and operation of electrical circuits, including integrated circuits (“ICs”). As an example, an IC itself may contain a number capacitors coupled with other components for the IC's operations, such as signal processing. In addition to internal capacitors, an IC may also rely on external capacitors to stabilize power supply, to absorb undesirable fluctuations, or to reduce signal interference or noise. For example, an IC mounted on a printed circuit board (“PCB”) may be coupled with ceramic capacitors that are also mounted on the PCB for one of those purposes, and the capacitors may be mounted using known surface mount technology (“SMT”). Alternatively, other types of capacitors may be mounted on or in the circuit board and coupled with the IC to provide similar effects as those SMT capacitors.
The coupling between an IC and external capacitors is generally achieved by constructing wiring paths, which may have a significant length compared to the couplings within the IC itself. In certain applications, the length of a winding or narrow path may create inductance from the path itself, leading to undesirable inductance effect affecting IC signals or operations. Additionally, SMT capacitors, although small in size, is also limited in its range of capacitances, the signal frequency it is capable of handling, or both. With the increasing speed of electrical circuits and other components and the shrinking size of devices and available PCB space, finding SMT capacitors that are capable of satisfying the design need becomes a challenge. Additionally, SMT capacitors mounted on a PCB requires certain board space and may limit the board space available for other devices. With the increasing terminals of IC and the densely arranged terminals, the wiring design for coupling the IC to external capacitors may also post another challenge.
Therefore, it may be desirable to provide a capacitor device that can be embedded into other structures, such as a circuit board. It may also be desirable to provide capacitor design that offers a wider range of capacitance. It may also be desirable to reduce the wiring paths from an IC to external devices such as capacitors or capacitive-inductive networks.